GAS-PERMEABLE MOLD

• Main Authors: TOMIOKA MASANORI, INAGAKI TAKEHIRO, MAKIGUCHI TADASHI, NISHIKAWA KAZUYUKI, FUMA TOYOJI
• Format: Patent
• Language: English
• Published: 18.10.1985
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CASTING; FOUNDRY MOULDING; PERFORMING OPERATIONS; POWDER METALLURGY; SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS, SLAG, OR MIXTURESCONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING CEMENT, CLAY, OR STONE; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

PURPOSE:To control gas permeability in each part of a mold by a method wherein an internal unbaked backing layer is removed leaving the fine hardened layer on the external circumference of a composite baked body to provide a cavity part and to fill the cavity part with fine particle material. CONSTITUTION:The composite baked body 1 is composed of metallic powder and ceramic powder, has a fine hardened layer 2 on the external circumference including a mold surface, and a backing layer 3 of unbaked mixed composition inside this hardened layer 2. Since caking agent is evaporated or burnt in a drying process and the baking process in oxidizied atmosphere, the hardened layer 2 is provided with about 5-10mum pores and with a porous but fine and smooth surface structure by these fine pores. The hollow mold 4 in which the unbaked backing layer 3 is removed is free from occurrence of cracks and made of the hardened layer 2 with an equal thickness.